The quest to build aircraft that can land straight down, lift straight up, hover in midair for a reasonable time, and then cruise off horizontally has continued for a number of years. The designs for this type of aircraft have included aircraft that employ engines attached to revolving main wings; air deflecting flexible curtains; wings with tunnels that contain wind directing airfoils and various other lifting airfoil configurations.
The majority of past and current vertical/short takeoff or landing (V/STOL) aircraft derive their vertical lift capability directly from the thrust provided by the propellers. Thus, the aircraft require engines with considerable power output and large diameter propellers. In some designs, the required propeller diameter is too large to allow the aircraft to make a conventional horizontal takeoff or landing, thereby restricting the aircraft to vertical takeoffs and landing.
In addition to the above problems, past aircraft have had their engines attached to the main wing. In some designs, the engines are solidly attached and revolve with the wing through a large angle of incidence when the wing rotates. In other designs, the engines are attached at the ends of the wings and rotate along with the propellers, thereby creating large inertial and gyroscopic forces. In some cases, this type of design requires an auxiliary propeller that is mounted in the tail of the fuselage normal to the longitudinal axis. The auxiliary propeller offsets the large pitching moments incurred as, for example, on the Canadian CL-84 V/STOL aircraft.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention however, the following U.S. patents were considered related:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 2,974,899 Fowler 14 March 1961 2,848,180 Ploger 19 August 1958 1,910,098 Ellis 23 May 1933 1,704,449 Waldy 5 March 1929 ______________________________________
The Fowler patent discloses a single propeller aircraft designed for vertical take-off or landing and for conventional flight. The aircraft includes a fixed airfoil, a fixedly mounted engine, and a mechanically controlled, flexible curtain that deflects the slipstream of the propeller downwardly to produce an upward force to achieve vertical movement. Also, included are opposing wing tip jets and a high velocity gas ducting system. The jets produce lateral stability and control of the airplane during vertical takeoff and landing motions and aid in lateral stability of the aircraft in conventional flight and through the transition from vertical movements to conventional flight. The gas ducting system allows air to be conducted from a gas compressor and admixing it with the engine exhaust to produce a stream of high velocity gas that is ducted to the wing tip jets.
The Ploger patent discloses an airplane tunnel type wing for improving the operating characteristics of an aircraft. The wings have longitudinally extending tunnels mounted on each side of the aircraft body. Within the tunnels are placed airfoils designed to direct airflow so that the aircraft may be directed to rise substantially vertically or move in a horizontal direction. The airfoils can be adjusted by the pilot so that the lift and direction of lift is controlled and may also be oppositely adjusted to allow the aircraft to turn.
The Ellis patent discloses an aircraft that can takeoff or land with very little or no forward motion. The aircraft is designed with adjustable auxiliary lifting planes that are positioned within a confined passage located on each side of the aircraft within the airstream. The planes deflect the airstream downwardly, thereby causing a sufficient lifting moment that allows the aircraft to rise or land with little forward motion. The propellers are located to cause practically their entire airstream to flow into the confined passage in which are positioned the planes.
The Waldy patent discloses an aircraft that consists, in effect, of two triple planes arranged in tandem. The design includes pair of transversely arranged and longitudinally spaced fixed wings and a pair of superposed wings having vertically movable sections and located intermediate to the fixed wings. In front of each fixed wing are located a plurality of propellers that produce the airstream that allows the fixed wings to produce the desired lifting effect and to direct the airstream to the superposed wings for further control. In operation, the superposed wings are lowered to produce a direct lifting force. For forward propulsion, the wings are raised to afford the desired speed.